1. Field of the Invention
The present invention relates to ignition systems and more particularly an ignition system for a propulsion producing engine that uses optical means for initiating the exothermic chemical reaction associated with so-called green fuels.
2. Description of the Related Art
Chemical hypergolic additives have long been used to initiate exothermic chemical reactions. These "hypergols" are highly reactive and highly toxic. In order to be deemed a non-toxic fuel, a small amount of hypergol can be added to the fuel directly. In such instance, there is sufficient hypergol to allow for the initiation of the reaction. Yet, its presence in a non-toxic fuel is of sufficient dilution that the fuel still qualifies as non-toxic. In summary, the fuel is maintained in a "green" classification by adding enough hypergol to the fuel to make it self-initiating in the presence of the oxidizer, but in such small quantities that its dilution in the fuel technically qualifies the mixture as non-toxic.
However, the presence of the hypergol in the fuel means that its performance is reduced. That is, once the mixture has begun to react, the hypergol's role is no longer necessary and it becomes, in essence, a contaminant, potentially reducing the propulsion performance. In practical terms, there is no long term storage data regarding whether this fuel hypergol mixture will remain viable in the long term.
U.S. Pat. No. 4,702,808, issued to J. H. Lemelson, entitled "Chemical Reaction Apparatus and Method" discloses rocket engine ignition in which propellants are ignited by an intense radiant energy, such as a light beam generated by a laser mounted in a housing. A beam of intense light is directed to the interior volume and caused to intersect fuel fed through inlets to effect ignition. There is no discussion in this patent of the photo-chemical interaction of the oxidizer and the fuel.
U.S. Pat. No. 5,727,368, issued to E. J. Wernimont, entitled "Hybrid Motor System with a Consumable Catalytic Bed a Composition of the Catalytic Bed and a Method of Using", discloses a method, device, and composition for achieving ignition and sustained combustion using a solid consumable catalytic bed. The consumable catalytic bed (CCB) accomplishes this by decomposition of an injected fuel. Initially, this reaction is catalytic or hypergolic in nature eventually becoming entirely thermal as the CCB is consumed in the reaction generated. The patent is directed to a hydrogen peroxide hybrid rocket.